Software that is available over the Internet with the ability to run behind a firewall on a local area network or personal computer may be known as Software as a Service (SaaS). The accessibility of SaaS continues to increase in a variety of areas, changing the mainstream model of computing. The SaaS approach has enabled recent advancements in cloud computing with the promise of low startup costs for infrastructure.
Technologies such as in-memory caching and web farms are in an excellent position to improve their service performance using SaaS, however, the use of traditional relational database management systems (RDBMS) as the backend data store still remains an integral part of such technologies. Typical database service providers may leverage traditional RDBMS multi-tenancy with shared schemas databases by collocating tenants into a number of databases which have the same schema. However, collocating tenants has a significant impact on the performance of the service. The collocation of tenants with extremely different data distributions or querying characteristics into the same database may lead to suboptimal performance of the underlying tenants.